This invention relates to an improved quench system and method for use in spinning multifilament synthetic fiber. More particularly, the system and method use a fog in the quench stack in combination with a flow of air.
By fog is meant fine particles of fluid, such as water suspended in air, specifically excluding fluid such as water droplets not suspended in air. This fog can be mechanically produced with an airless spray nozzle (atomizer) to atomize fluid such as water. Such an airless spray nozzle is disclosed in U.S. Pat. No. 3,366,721 hereby incorporated by reference. By fluid is meant any fluid which can absorb a great deal of heat, such as by the latent heat of vaporization of water or possibly liquid gases. Fluid also means mixtures of water with other fluids beneficial to fibers, such as finishes.
Although it is known to use flowing air to quench freshly spun filaments, and it is known to use airless spray fog or colloidal suspension of fluid, such as water (U.S. Pat. No. 3,366,721) alone to quench filaments, the combination is not taught. Each of these methods when used alone is uneconomical in capital investment or require high flow rates causing filament motion, undesirable for reasons given below.
Because a large volume of air at high velocity is necessary to create the water spray, the prior art method of using flowing air and sprayed water from a compressed air spray nozzle to quench filaments creates great turbulence of the filaments in the quench stack causing at worst filaments fusing together, or at best slight imperfections where the filaments touch or brush one another in the quench stack. Also, turbulence can cause denier variation. These fusions and even denier variation or slight imperfections then cause major problems in subsequent continuous processing of continuous filaments as they break, slough, or wrap on rolls in the drawing, twisting, texturing or like equipment.
Use of steam to condition fiber in the quench stack is also known, but does not utilize the latent heat of vaporization to cool the filaments which is available by use of fog.
Also, use of sprays of water droplets on the yarn is known but cause undesirable non-uniformities along the filament. In fact, such nonuniformity is used to intentionally create weak spots or to create crinkled fiber.